1. Field of the Invention
The present invention relates in general to a countershaft synchromesh type transmission and more particularly to an improved arrangement suited for use as an automotive automatic transmission.
2. Description of the Prior Art
"Automotive Engineering" June 1980 pages 87 and 88 shows a synchromesh type transmission which performs so called "hot shifts" between gears by setting synchronizers and selectively engaging and disengaging first and second clutches. However, this transmission has suffered from the drawback that the sequential 1-2-3-4-5 etc., up and down shift must be performed. That is, in such transmission, it is impossible to skip over a gear and shift from first to third or vice versa, for example.
In order to solve the drawback of such transmission, the applicant has previously proposed, in Japanese Patent Application First Publication No. 58-118355 (which has corresponding U.S. patent application Ser. No. 454,005) and Japanese Patent Application No. 58-169325, improved synchromesh type automatic transmissions. In these transmissions, it is possible to skip over gears and perform non-sequential up and down shifts when desired.
However, also these prior proposed transmissions have suffered from another drawback that the structure for bearing or rotatably supporting a given (that is, third speed) input gear is very complicated. That is, in the prior proposed arrangements, respective synchronizers must be arranged at either side of the "single" third speed input gear for connecting the gear with first and second intermediate shafts selectively. This arrangement makes the supporting structure for the third speed input gear complicated.